The use of high-power fiber-coupled lasers continues to gain popularity for a variety of applications, such as materials processing, cutting, welding, and/or additive manufacturing. These lasers include, for example, fiber lasers, disk lasers, diode lasers, diode-pumped solid state lasers, and lamp-pumped solid state lasers. In these systems, optical power is delivered from the laser to a work piece via an optical fiber.
Various fiber-coupled laser materials processing tasks require different beam characteristics (e.g., spatial profiles and/or divergence profiles). For example, cutting thick metal and welding generally require a larger spot size than cutting thin metal. Ideally, the laser beam properties would be adjustable to enable optimized processing for these different tasks. Conventionally, users have two choices: (1) Employ a laser system with fixed beam characteristics that can be used for different tasks but is not optimal for most of them (i.e., a compromise between performance and flexibility); or (2) Purchase a laser system or accessories that offer variable beam characteristics but that add significant cost, size, weight, complexity, and perhaps performance degradation (e.g., optical loss) or reliability degradation (e.g., reduced robustness or up-time). Currently available laser systems capable of varying beam characteristics require the use of free-space optics or other complex and expensive add-on mechanisms (e.g., zoom lenses, mirrors, translatable or motorized lenses, combiners, etc.) in order to vary beam characteristics. No solution exists that provides the desired adjustability in beam characteristics that minimizes or eliminates reliance on the use of free-space optics or other extra components that add significant penalties in terms of cost, complexity, performance, and/or reliability. What is needed is an in-fiber apparatus for providing varying beam characteristics that does not require or minimizes the use of free-space optics and that can avoid significant cost, complexity, performance tradeoffs, and/or reliability degradation.
Porous structures are commonly used for the creation of lightweight components, filtration, sorption media and acoustic dampening. These properties make porous structures very useful. Often, porosity characteristics within a single bulk material are held relatively constant by the manufacturing process, although this is not so in the case of polymer foams, which may have a non-porous skin created on the outer surfaces. Manufacturing techniques for porous objects materials often employ assemblage with additional structures to be useful, which raises the cost and complexity of those items. Furthermore, the porous areas within the assembled structure are limited to the fixed porosity of the individual porous component.
It is noted that while additive manufacturing techniques, also referred to as 3D printing, can create voids in material. However, the resolution of the voids and/or the ability to vary or otherwise tailor the porosity is limited.
Therefore, manufacturing processes that allow tailoring of pore structures and/or porosity, and that can efficiently manufacture materials of varied pore structure and/or porosity would be a welcome addition to the art.